Chronic Obstructive Pulmonary Disease & Emphysema

Description of Medical Condition

Chronic obstructive pulmonary disease (COPD) encompasses several diffuse pulmonary diseases including chronic bronchitis, asthma, cystic fibrosis, bronchiectasis, and emphysema. The term usually refers to a mixture of chronic bronchitis and emphysema. COPD is characterized by airflow limitation that is not fully reversible.

• Chronic bronchitis is defined clinically by increased mucus production and recurrent cough present on most days for at least three months during at least two consecutive years.
• Emphysema is the destruction of interalveolar septa. The disease occurs in the distal or terminal airways and involves both airways and lung parenchyma.

System(s) affected: Pulmonary

Genetics:

• Chronic bronchitis is not a genetic disorder although some studies have hinted at a predisposition for development of this condition.
• A rare form of emphysema, antiprotease deficiency (due to alpha 1 -antitrypsin deficiency), is an inherited disorder that is an expression of two autosomal codominant alleles.

Incidence/Prevalence in USA:

• 10-20% of adults; more than 100,000 deaths/year (4th most common cause of death)
• 14 million people have chronic bronchitis; 2 million people have emphysema
• Fourth leading cause of death in the United States

Predominant age: Over 40 years

Predominant sex: Male > Female

Medical Symptoms and Signs of Disease

Chronic bronchitis

• Cough
• Sputum production
• Frequent infections
• Intermittent dyspnea
• Hemoptysis
• Morning headache
• Pedal edema
• Plethora
• Cyanosis
• Wheezing
• Weight gain
• Diminished breath sounds
• Distant heart sounds

Emphysema

• Minimal cough
• Scant sputum
• Dyspnea
• Often significant weight loss
• Occasional infections
• Barrel chest
• Minimal wheezing
• Use of accessory muscles of respiration
• Pursed lip breathing
• Cyanosis is slight or absent
• Breath sounds very diminished
• Weight loss

What Causes Disease?

• Cigarette smoking
• Air pollution
• Antiprotease deficiency (alpha-1 antitrypsin)
• Occupational exposure (i.e., firefighters, dusty jobs)
• Infection possibly (viral)
• Occupational pollutants (cadmium, silica)

Risk Factors

• Passive smoking (especially adults whose parents smoked)
• Severe viral pneumonia early in life
• Aging
• Ethyl alcohol (EtOH) consumption
• Airway hyperactivity
• Socioeconomic (more common in low socioeconomic status)
• Dietary (vitamin C and E deficiency)

Diagnosis of Disease

Differential Diagnosis

Acute bronchitis, asthma, bronchiectasis, bronchogenic carcinoma, acute viral infection, normal aging of lungs, occupational asthma, chronic pulmonary embolism, sleep apnea, primary alveolar hypoventilation, chronic sinusitis, reactive airways dysfunction syndrome (RADS), congestive heart failure

Laboratory

Chronic bronchitis

• Hypercapnia
• Poiycythemia
• Hypoxia can be moderate to severe

Emphysema

• Normal serum hemoglobin or poiycythemia
• Normal PaC02; unless FEV1 < 1 L, then can be elevated
• Mild hypoxia — especially at night

Drugs that may alter lab results: Sedatives including alcohol

Disorders that may alter lab results: Obesity, concurrent restrictive lung dysfunction, primary pulmonary hypertension, acute infections, anemia, pulmonary embolism, sleep apnea, congestive heart failure

Pathological Findings

Chronic bronchitis

• Bronchial mucous gland enlargement
• Increased number of secretory cells in surface epithelium
• Thickened small airways from edema and inflammation
• Smooth muscle hyperplasia
• Mucus plugging
• Bacterial colonization of airways

Emphysema

• Entire lung affected
• Bronchi usually clear of secretions
• Anthracotic pigment
• Alveoli enlarged with loss of septa
• Cartilage atrophy
• Bullae

Special Tests

Pulmonary function testing

• Decreased FEV1 with concomitant reduction in FEV1/FVC ratio
• Poor or absent reversibility to bronchodilators
• FVC may be normal or reduced
• Normal or increased total lung capacity
• Increased residual volume
• Diffusing capacity is normal or reduced

Nocturnal oximetry

Imaging

• Chronic bronchitis chest x-ray shows increased bron-chovascular markings and cardiomegaly
• Emphysema chest x-ray shows small heart, hyperinflation, flat diaphragms and possibly bullous changes
• CAT scan may show bullous changes, especially if it is high resolution

Diagnostic Procedures

• Pulmonary function tests
• ABGs
• Chest x-ray

Treatment (Medical Therapy)

Appropriate Health Care

• Outpatient treatment is usually adequate. However, hospitalization may be required for exacerbation, infection, or diagnostic procedures (i.e., transbronchial lung biopsy).
• Acute respiratory failure may require an intensive care unit and possibly a mechanical ventilator to support the patient

General Measures

• Smoking cessation
• Aggressive treatment of infections
• Treat any reversible bronchospasm
• Reduction of secretions through good pulmonary hygiene
• Cor pulmonale may necessitate use of home oxygen
• Pulmonary rehabilitation
• Appropriate vaccinations
• Adequate hydration

Surgical Measures

• Lung reduction surgery (selected cases)
• Lung transplantation (selected cases)
• Bullectomy (selected cases)

Activity

As tolerated. Full activity should be encouraged.

Diet

A well balanced, high protein diet is suggested. Low carbohydrates may benefit those with hypercarbia.

Patient Education

• Printed material is available from the National Jewish Hospital in Denver, Colorado. The local branch of the American Lung Association also has educational material.
• Coach patients in pulmonary rehabilitation

Medications (Drugs, Medicines)

Drug(s) of Choice

• Theophylline (Theo-Dur, Unidur, Uniphyl) 400 mg/day. ncrease by 100-200 mg in one to two weeks if necessary.
• Sympathomimetics — e.g., metaproterenol (Alupent), albuterol (Proventil, Ventolin), pirbuterol (Maxair), 1-2 puffs from the metered dose inhaler every 4-6 hrs. May be increased to every 3 hrs. Use of spacer device (AeroChamber, Inspirease) may be beneficial. (Up to 4 puffs recommended by some.) Long acting sympathomimetics — salmeterol (Serevent) orformoterol (Foradil) to be considered.
• Anticholinergics
  • Ipratropium (Atrovent) two puffs (36 μg) 4 times daily
  • May take additional inhalations not to exceed 12 in 24 hrs.
  • Tiotropium (Spiriva), one puff daily
• Corticosteroids — prednisone (Deltasone). Given orally 7.5-15 mg/day. Most useful in bronchitis with some reversibility. Inhaled corticosteroids also may be beneficial with less side effects.
• Purified human alpha 1-antitrypsin for patients with this deficiency — 60 mg/kg weekly to maintain level more than 80 mg/dL
• Mucolytic agents may improve secretion management

Contraindications:

• Theophylline — hypersensitivity
• Sympathomimetics — cardiac arrhythmias associated with tachycardia; hypersensitivity
• Anticholinergics — hypersensitivity to atropine or its derivatives
• Corticosteroids — systemic fungal infections; hypersensitivity

Precautions:

• Theophylline — reduce dosage in patients with impaired renal or liver function; age over 55; CHF. Therapeutic drug level is 5-15 /jg/mL (55.5-111 /jmol).
• Rifampin — may cause a decrease in theophylline levels by increasing theophylline metabolism. Monitor serum theophylline level.
• Sympathomimetics — excessive use may be dangerous. May need to reduce dose in patients with cardiovascular disease, hypertension, hyperthyroidism, diabetes or convulsive disorders.
• Anticholinergics- narrow angle glaucoma, prostatic hypertrophy, bladder-neck obstruction
• Corticosteroids — may mask infection or predispose to infection, especially fungal; subcapsular cataracts: glaucoma; adrenocortical insufficiency; psychic derangements; gastrointestinal bleeding; diabetes mellitus, reactivation of tuberculosis

Significant possible interactions:

• Theophylline — lithium carbonate; propranolol; erythromycin; cimetidine; ranitidine; rifampin; ciprofloxacin

Addition of cimetidine, ciprofloxacin, or erythromycin will decrease theophylline clearance causing theophylline levels to rise. Careful monitoring of serum theophylline levels is warranted. (Note: cimetidine is now an OTC drug.)

• Sympathomimetics — other sympathomimetics, mono-amine oxidase inhibitors or tricyclic antidepressants
• Anticholinergics — refer to manufacturer’s profile
• Corticosteroids — NSAIDs (indomethacin), aspirin, synthetic thyroid hormone

Alternative Drugs

• Theophylline may be given orally, intravenously or by rectal suppository
• Sympathomimetics may be given as aerosolized solution (albuterol, metaproterenol [Metaprel], levalbuterol. isoetharine) when mixed with saline; orally (Alupent, Proventil, Brethine, Ventolin) or subcutaneously (terbutaline)
• Anticholinergics — atropine sulfate, glycopyrrolate pratropium (Atrovent) now available in aerosolized solution and may be mixed with albuterol.
• Corticosteroids may be given intravenously (hydrocorti-sone, methylprednisolone) or inhaled (beciomethasone. flunisolide, triamcinolone acetonide)
• Home oxygen

Patient Monitoring

• Severe or unstable patients should be seen monthly
• When stable, may be seen biannually
• Check theophylline level with each dose adjustment until the desired level (or result) is achieved, then check every 6-12 months
• With home oxygen, check arterial blood gasses yearly or with any change in condition. Monitor oxygen saturation (pulse oximetry) more frequently.
• Some patients only desaturate at night thereby only needing nocturnal oxygen
• Avoid travel at high altitude. Air travel with oxygen requires pre-arrangement.
• Discuss advanced directive in severe cases

Prevention / Avoidance

Avoidance of smoking is the most important preventive measure. Passive smoke also has been shown to be harmful. Early detection may be useful in preserving remaining lung function.

Possible Complications

• Infection is common

• Cor pulmonale, secondary polycythemia, bullous lung disease, acute or chronic respiratory failure, pulmonary hypertension, malnutrition, pneumothorax, poor sleep quality, arrhythmias, acute respiratory failure

Expected Course / Prognosis

• The patient’s age and post-bronchodilator forced expiratory volume (FEV1) are the most important predictors of prognosis. Young age and FEV1 > 50% predicted to have a good prognosis. Older patients with more severe lung disease do worse.
• Supplemental oxygen, when indicated, has been shown to increase survival
• Smoking cessation is also important for an improved prognosis
• Malnutrition, cor pulmonale, hypercapnia and pulse > 100 indicate a poor prognosis

Miscellaneous

Associated Conditions

• Lung cancer
• Coronary artery disease
• Peptic ulcer disease
• Chronic sinusitis
• Malnutrition
• Laryngeal carcinoma
• Acute bronchitis
• Sleep apnea

Age-Related Factors

Pediatric

Repeated childhood respiratory illnesses make COPD a greater risk

Geriatric

Relative risk is 1.2 to 2.3 times greater than in younger person

Others

Unusual under age 25 unless antiprotease deficiency is present. Incidence increases as age approaches 60.

Pregnancy

N/A

Synonyms

• Bronchitis
• COLD (Chronic obstructive lung disease)
• OAD (Obstructive airways disease)
• COPD

International Classification of Diseases

496 Chronic airway obstruction, NEC

492.8 Other emphysema

See Also

Asthma Bronchitis, acute

Other Notes

• Albuterol is also known as salbutamol
• Other important considerations for treatment include adequate hydration, supplemental oxygen, antibiotics when indicated, mucolytic agents, pulmonary rehabilitation, good pulmonary hygiene

Abbreviations

FVC = forced vital capacity FEV1 = forced expiratory volume at 1 second COPD = chronic obstructive pulmonary disease ABG = arterial blood gases